A scanning and transmission electron microscopic study of urinary bladders of mice treated with 2-acetylaminofluorene.

Urinary bladders of BALB/c male mice treated with 250 ppm of 2-acetylaminofluorene for 1, 3, 5, 7, and 14 days were examined for early scanning (SEM) and transmission electron microscopic (TEM) changes. SEM observations at days 1, 3, and 5, and TEM observations at days 1 and 3 revealed no significant changes. The bladders of the mice treated for 7 days contained an occasional focus showing irregularity in the shape and size of the superficial cells and SEM revealed ropey microridges in an occasional cell. The bladders of mice treated for 14 days had a greater irregularity of cell size on SEM. TEM changes were evident as early as 5 days with an increase in severity at 7 and 14 days. A numerical reduction of fusiform vesicles, asymmetric membrane plaques and Golgi apparatus along with an increase in membranous whorls, endoplasmic reticulum, cytolysosomes, and small rounded vesicles was evident. The study may aid in a better understanding of early morphologic changes of urothelium in response to a carcinogen.